Geography Study Materials and Hand-outs

GIS Spatial Data Model Traditionally spatial data has been stored and presented in the form of a map. Three basic types of spatial data models have evolved for storing geographic data digitally. These are referred to as: ü       Vector Data Model ü       Raster Data Model                   Vector Data ü        Map features o         Points, lines, polygons o         Feature attributes ü        Every feature has attributes o         (e.g. name, area, population) Raster Data Stored electronic image or picture taken as an aerial photograph or satellite image. Composed of a rectangular array of square cells, called pixels, with a number in each cell representing the solid color fill of that cell. A new hybrid method of storing data is that of identifying point clouds, which combine three-dimensional points with RGB information at each point, returning a "3D color image". GIS thematic maps then are becoming more and more re